<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div id="qrcode"></div>
    <script src="../jquery-3.1.1.min.js"></script>
    <script src="jquery.qrcode.min.js"></script>
    <script>

        $('#qrcode').remove("canvas").qrcode({width: 64,height: 64,text: "size doesn't matter"});
        setTimeout(function () {
            $('#qrcode canvas').remove();
        }, 1000)

    </script>
    <script>
        // (async () => { console.log(1) } )()
        let o = {a: 1},
            b = {a: 2};
        let j = {
            a: 1,
            arrow: () => {
                console.log( this )
                this.a
            }
        }
        let s = {
            a: 2
        }
        s.arrow = j.arrow;
        s.arrow();
        console.log( s.arrow() )
        // let arrow = () => this.a;
        // arrow.call( o )

        // function * a() {
        //     yield this.a;
        //     // yield b;
        //     console.log(this.a)
        //     let s = yield b
        //     console.log( s * 10 )
        // }
        // var s = a.call( o )
        // var q = a.call( b )
        // console.log(s.next(10))
        // console.log(s.next(10))
        // console.log(s.next(10))
        // console.log(s.next())
        // console.log(s.next())
        // console.log(s.next())
        // console.log(q.next())
        // console.log(q.next())
    </script>
</body>
</html>